Not just slime! Wastewater-grown algae used to heat buildings

Algal blooms have caused headaches for plant operators over the years yet a US-French collaboration called Ennesys believe that algae grown from wastewater can be recycled and used to generate heat in building panels...

Algal blooms have caused headaches for plant operators over the years yet it is becoming increasingly common to now harness nutrients produced in wastewater and infact grow algae and turn it into energy.

A partnership between US firm OriginOil and French-based Ennesys believe that algae from wastewater can be recycled and used to generate heat in flat, building panels.

Founded in 2010, the joint venture believes that by installing “photobioreactors” – thin panels - to a building’s façade, algae can be added to generate energy for that very structure.

The plan is for wastewater to be taken from a building’s bathrooms and kitchens and algae would then feed off of the nutrients, such as phosphorous and potassium. The addition of the algae gives the panels their green colouring.

“This new concept of algae being grown vertically and also on roofs so that a building can actually purify its own water and provide some energy,” said Riggs Eckelberry, CEO of OriginOil.

In its company video, the US firm described how its Algae Appliance Model 4 trial system worked. In single step extractor tubes, algae is collected into clumps. It is then floated up so that it’s collected on the surface as bubbles.

It is then transferred to the conveyor belt where solids are extracted onto a hopper. While OriginOil did not give away details of its energy extraction process, it said that 95% of the wastewater can be removed, leaving 5% solids.

Earlier this year the first Model 4 system was shipped to Ennesys in France, to be integrated with the company’s “wall growing system”. A demonstration pilot was installed in the office complex of Paris’ La Défense business district.

In a company statement, OriginOil said: “The Ennesys demonstration is designed to test the suitability of algae production in helping large commercial buildings achieve a positive energy balance and natural water management, as envisioned by France’s RT 2020 sustainable energy framework. Partial funding is anticipated from regional government entities.”

France’s sustainable energy law – the RT 2020 – requires all major buildings to achieve a positive energy balance by the end of the decade.

Ennesy CEO Pierre Tauzinat, told Reuters: “Wastewater is full of nutrients. We are preparing wastewater is a way that phytoplankton and microalgae will nourish themselves from everything that is inside this wastewater. What you have is a perfect biomass that’s made of phytoplankton that’s grown in 24-48 hours and on the other side, you will have pure water.”

OriginOil’s second licensing agreement will target oil service companies in the Canadian oil sands market. The agreement will see investor LH Opportunity Group bundle the system together with fabricator Ensteel Industries for potential applications in enhanced oil recovery and tailing pond water treatment markets.

Nor is it just in France where nutrients from wastewater are being used to help grow algae.

Earlier this year US President Barack Obama announced that the Department of Energy would make $14 million available to support research and development into biofuels from algae. The Department has suggested that up to 17% of the US' imported oil for transportation could be replaced with biofuels derived from the substance.

In Europe, a €12 million, five-year project is starting at water management company aqualia's wastewater treatment plant in Chiclana, Southern Spain and is backed by the European Union as part of its FP7 program – supporting energy-related projects - with six partners.

Called All-Gas, which translates into algae in Spanish, the project will see "algal culture ponds" being used to grow micro-algae using nutrients contained in wastewater, such as phosphorous. A 10-hectare site will eventually be needed for the project (read Water & Wastewater International story).

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